It said steps included newsletters to staff suggesting they should avoid comments on political issues like PPE on social media, as well as posters put up in staff areas urging healthcare workers not to make public appeals for equipment or donations.

The Department of Health has said that nobody should be prevented from speaking up about the issue.

The programme comes after a BBC Panorama investigation previously revealed the government failed to stockpile crucial PPE ahead of the coronavirus pandemic.

“Those who have been speaking out have then received a reprimand or they’ve had a warning… that their contracts are likely not to be replaced.”

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“They kept on feeding me what felt like government type of lines, saying 'this hospital has never had PPE shortages' - which I know to be factually untrue,” he said.

Another doctor told Newsnight they were called into a meeting with senior managers after speaking to the media about PPE shortages and warned they might find it hard to get a job if they got a ‘reputation’.

Yahoo had been due to speak to an NHS worker for one of our podcasts, but she cancelled as she was told not to by her employers.

I appeared tonight on @BBCNewsnight discussing whistleblowers in the NHS. Those who speak up against wrongdoing in the workplace, whichever sector or industry, need the protection to expose failings in the system without fear of reprisal. pic.twitter.com/bjY3FhHcKw

Georgina Halford-Hall, chief executive of WhistleblowersUK, told Newsnight that the default position was “an auto-immune response against the whistle-blower”.

She said: “Those who have been speaking out have then received a reprimand or had a warning, especially the locum consultants, that their contracts are likely not to be replaced again at the end of their term and that they are going to find themselves unemployed and likely not to be able to find a job.

“We’re losing the most important members of staff - those who speak up.”

Conservative MP Mary Robinson, who is chair of the all-party parliamentary group for whistleblowing and appeared in the Newsnight programme, tweeted: “Those who speak up against wrongdoing in the workplace, whichever sector or industry, need the protection to expose failings in the system without fear of reprisal.”

A Department of Health and Social Care spokesperson told the BBC: "Whistleblowers perform a vital and courageous service in ensuring safe care, and no one should ever be prevented from speaking up or discriminated against if they do.

"Freedom to Speak Up Guardians are now established in every NHS trust in England to ensure workers who speak up are listened to, thanked and supported, and they have handled over 19,000 cases in the last two years."